Last week, the actor Catherine Zeta-Jones confirmed she had spent five days at a psychiatric hospital in Connecticut, being treated for bipolar disorder. Mental health charities, including Sane and Time To Change, praised the star for her open attitude towards the illness, and welcomed the media focus on the condition. But what is it like to live with an illness which causes severe mood swings – from periods of depression to mania (hyperactivity and excitedness)? And does hearing about the mental health of celebrities help?

Siobhan O'Neil, 47, from south London

I wasn't diagnosed with bipolar disorder until I was 39, although I'd been showing signs of the illness since my teens. I had always been thought of as sensitive – I'd often get quite weepy – and creative, because I was really into drama and theatre. So, in my manic periods, when I'd suddenly have an excess of energy, people would just accuse me of being a drama queen.

When I was 19, I became very depressed after a relationship ended, and made an attempt on my life. That was how it was throughout my 20s: I'd have episodes of incredible energy and positivity, when I'd have loads of great ideas and exhaust my friends wanting to go out every night. I wouldn't be able to sleep. But eventually my body would become exhausted, I'd get tired and irritable, and then tip over into periods of feeling incredibly down. But I didn't realise there was anything wrong with me – as far as I was concerned, I'd just always been this way.

I got bored really easily – I went from job to job, working in bars and in a communications company, until I finally became a BBC radio producer . That suited my "high" periods perfectly – I needed lots of energy to do the job, and again, people thought of me as a creative person. It was only after I was made redundant, and had a breakdown, that the diagnosis was finally made. I was given a mix of anti-depressants and sodium valproate – an alternative to lithium, which helped to stabilise me chemically. But even more important are the changes I've made to my lifestyle. I do a lot of exercise, I dance, I sing, I work in my allotment – all these things help me to feel better by calming me down and taking me out of myself.

When a celebrity like Catherine Zeta-Jones says they have experienced mental illness, the media does take a sudden interest – but that can never be a bad thing. It's incredibly important that people who have bipolar disorder, or any form of mental illness, feel they can talk about it. Initially, I found talking about my own history very difficult – but I do it in order to get the conversation going. Someone like Zeta-Jones can get that conversation going in a big way.

Sam Goold, 37, from Southampton

My diagnosis came after several months of treatment. I was 27, and had been working incredibly hard as a TV researcher. Work was my life – I'd moved from Southampton to London, and felt very isolated, so I spent evenings and weekends working. Then, when a programme I was working on went wrong, I couldn't cope, and I had my first manic episode. My own form of bipolar disorder is reactive – stressful situations such as redundancy or bereavement can tip me into a high.

The highs are intense: you experience great flights of fancy, and it's as if you can see the connections between everything in the world. I remember once looking at birds flying, and feeling like I was seeing them fly for the first time. But it doesn't last; eventually you realise you're unwell, and pushing yourself too far – then a low period follows.

I've been quite lucky, though: I was admitted for treatment while I was still more or less on a high – and the medication I was put on, lithium, has allowed me to balance out the worst of the lows.

When I was first diagnosed as bipolar, I felt ashamed; I didn't tell the girlfriend I was with at the time, which I now regret. But when I met my new partner, she somehow knew; her father was bipolar too, so she has some experience of the condition. We have two daughters now, and family life helps me enormously; it's important for my condition to find more of a balance between work and family, and to appreciate small, everyday things.

I've just been made redundant from my job as a mental health worker, which is very tough. But 10 years ago, before I was diagnosed and treated, I really don't think I could have coped with it.

For more information about bipolar disorder and any other aspect of mental health, visit www.mind.org.uk